The present invention relates to cleaning equipment for tubes and piping and, in particular, to high-pressure water spray systems for cleaning the bores of tubes mounted in a variety of equipment, such as heat exchangers, falling pressure evaporators and the like.
Industrial piping systems of all types frequently require cleaning. A problem especially common to heat exchangers and evaporators is that over time the bore and exterior walls of the heat exchange tubes develop corrosion, scale and other undesired residue. The buildup of residue decreases and/or generally adversely effects the heat transfer efficiencies. Restriction of the bore is especially critical. Operating costs for fuel, in turn, increase.
Periodic maintenance is thus required to clean the tubes, on the order of once or twice a year. Frequently the equipment and/or large sections of an operating plant must be taken off-line during maintenance. Such maintenance can be performed by plant personnel or outside contractors who are specially trained and use special purpose equipment to perform such tasks. It is desirable that any down time be minimized. The task is typically performed manually and is therefore costly and time consuming, especially for large heating and cooling plants.
A variety of techniques and types of equipment have been developed to clean the interior and exterior surfaces of pipes and particularly heat transfer tubes. Soot blowing and chemical shocking are two techniques. Another technique is to individually direct equipment into each tube to mechanically dislodge the residue from the tube walls. Some of the latter equipment uses rigid lances that either rotate and/or have rotating blades. U.S. Pat. No. 5,579,726 discloses a lance-based assembly that directs streams of high-pressure water to effect the cleaning. The latter system supports a rotating and axially directed lance from a frame that can be aligned to each tube.
High-pressure spray systems are also known that direct streams of water from a spray hose into each tube. Jetting Systems & Accessories, Inc. sells one such system under the brand name “FLEX LANCER”. Another system is sold by Gardner Denver Water Jetting Systems, Inc., Houston, Tex. under the name “V” Drum Rotary Line Cleaner. The latter system provides a high-pressure hose and spray nozzle that are rotated and axially directed under power. Hose movement is directed with a hand-operated air controller and a pinch roller assembly that controls axial hose movement. Rotational movement is controlled via a separate motor. The hose is collected and dispensed from a rotating V-shaped spool or drum. Although offering advantages, the efficiency of the latter system is severely restricted by vibrations that occur due to unbalanced conditions that can occur at the equipment during typical use. Extreme vibrations have particularly been experienced at speeds approaching 60 rpm, which severely limits the utility of the equipment.
The present invention was developed to provide a more efficient high-pressure spray system. The assembly provides a hose mounted spray head or nozzle that can be operated at rotational speeds in the range of 60 rpm to 850 rpm. Axial speeds in the range of 1 foot per minute to 80 feet per minute are also possible. At a nominal rotary speed of 300 rpm and an axial speed of 60 feet per minute, the assembly is able to clean a typical 36-foot tube in one-fourth the time as the foregoing equipment.
The assembly is constructed to provide optimal balance along the entire drive train. The assembly can also clean the exterior surface of the spray hose as it is dispensed and collected from a driven spool or reel assembly. The reel assembly stacks the hosing in a tapered coil that is balanced to the longitudinal drive axis of the hose drive train. The hub of the reel assembly can be adjusted to accommodate different lengths and diameters of hose. The reel hub can be open or covered to prevent the buildup of debris within the reel and/or prevent the hose from being ejected from openings in the interior and exterior peripheral surfaces.
An improved, air powered modular cleaning assembly is also disclosed. The hose drive assembly and hose reel assembly are modularly configured and clamped to a framework. An extension sheath and improved operator control gun separately latch to each other and an air swivel. Pneumatic control is directed via operator-actuated valves, contiguous control lines, hose and pinch wheel drive motors, a hose reel brake, and associated volume booster and timer controls. The hose drive assembly is driven and the hose reel assembly follows.